PHP verification code generation and verification example_PHP tutorial

Verification code is a common function in WEB2.0 now. Registration, login or message pages all require a registration code to verify the legitimacy of the current operator. We will see that some websites do not have verification codes. , but that is a more advanced verification. Let’s look at the commonly used verification code generation and usage methods.

1 A simple verification code example

1.1 Picture showing verification code

The code is as follows

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代码如下	复制代码
$num=intval(mt_rand(1000,9999));     for($i=0 ; $i     {echo "";}     ?>

$num=intval(mt_rand(1000,9999));
for($i=0; $i {echo "";}
?>

1.2 Verification process

代码如下	复制代码
if (strval($inputyzm)!=strval($num))     {     echo "<script>alert('验证码错误！');history.go(-1);</script>";     exit;     }

The code is as follows	Copy code
if (strval($inputyzm)!=strval($num)) { echo "<script>alert('Verification code error!');history.go(-1);</script>"; exit; }

2 A Chinese character verification code example

2.1 Picture showing verification code

代码如下	复制代码
$str="汉","字","验","证","码"); //可以定义汉字的内容和个数     $word=strlen($str));     for ($i=0;$i     {     $num=rand(0,$word);     $img = $img."";     $pic = $pic.$str[$num];     }     >

2.2 Assign the generated random string to a hidden field

代码如下	复制代码

代码如下	复制代码

2.3 Define a check() function

The code is as follows	Copy code

See a complete example

Examples of generating and calling PHP verification codes, which are often used in daily development. Please record them.

1. Verification code generation file code.php

The code is as follows

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代码如下

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Header("Content-type:image/png");     //定义header，声明图片文件，最好是png，无版权之扰;     //生成新的四位整数验证码     session_start();//开启session;     authnum_session = '';     str = 'abcdefghijkmnpqrstuvwxyz1234567890';     //定义用来显示在图片上的数字和字母;     l = strlen(str); //得到字串的长度;     //循环随机抽取四位前面定义的字母和数字;     for(i=1;i     {     num=rand(0,l-1);     //每次随机抽取一位数字;从第一个字到该字串最大长度,     //减1是因为截取字符是从0开始起算;这样34字符任意都有可能排在其中;     authnum_session.= str[num];     //将通过数字得来的字符连起来一共是四位;     }     session_register("authnum_session");     //用session来做验证也不错;注册session,名称为authnum_session,     //其它页面只要包含了该图片     //即可以通过_SESSION["authnum_session"]来调用     //生成验证码图片，     srand((double)microtime()*1000000);     im = imagecreate(50,20);//图片宽与高;     //主要用到黑白灰三种色;     black = ImageColorAllocate(im, 0,0,0);     white = ImageColorAllocate(im, 255,255,255);     gray = ImageColorAllocate(im, 200,200,200);     //将四位整数验证码绘入图片     imagefill(im,68,30,gray);     //如不用干扰线，注释就行了;     li = ImageColorAllocate(im, 220,220,220);     for(i=0;i     {//加入3条干扰线;也可以不要;视情况而定，因为可能影响用户输入;     imageline(im,rand(0,30),rand(0,21),rand(20,40),rand(0,21),li);     }     //字符在图片的位置;     imagestring(im, 5, 8, 2, authnum_session, white);     for(i=0;i     {//加入干扰象素     imagesetpixel(im, rand()%70 , rand()%30 , gray);     }     ImagePNG(im);     ImageDestroy(im);     ?>

Header("Content-type:image/png");
//Define header, declare image file, preferably png, no copyright interference;
//Generate a new four-digit integer verification code
Session_start();//Open session;
authnum_session = '';
​ str = 'abcdefghijkmnpqrstuvwxyz1234567890';
//Define the numbers and letters used to display on the picture;
l = strlen(str); //Get the length of the string;
//Loop and randomly select four letters and numbers defined previously;
for(i=1;i {
num=rand(0,l-1);
// Randomly select a number each time; from the first word to the maximum length of the string,
//Minus 1 because the intercepted characters start from 0; in this way, any 34 characters may be ranked among them;
authnum_session.= str[num];
//The characters obtained by numbers are connected to a total of four digits;
}
Session_register("authnum_session");
//It’s also good to use session for verification; register session, the name is authnum_session,
//As long as other pages contain this image
//You can call through _SESSION["authnum_session"] //Generate verification code image,
srand((double)microtime()*1000000);
im = imagecreate(50,20);//Picture width and height;
//Mainly use three colors: black, white and gray;
Black = ImageColorAllocate(im, 0,0,0);
White = ImageColorAllocate(im, 255,255,255);
Gray = ImageColorAllocate(im, 200,200,200);
//Draw the four-digit integer verification code into the picture
Imagefill(im,68,30,gray);
//If no interference lines are needed, just comments;
li = ImageColorAllocate(im, 220,220,220);
for(i=0;i {//Add 3 interference lines; it may not be necessary; it depends on the situation, because it may affect user input;
Imageline(im,rand(0,30),rand(0,21),rand(20,40),rand(0,21),li);
}
//The position of the character in the picture;
Imagestring(im, 5, 8, 2, authnum_session, white);
for(i=0;i {//Add interference pixels
imagesetpixel(im, rand()%70, rand()%30, gray);
}
ImagePNG(im);
ImageDestroy(im);
?>

The above code refers to the following article:
php image verification code
Example of php generating verification code
Use php to generate verification code with snowflake background

2. The page that calls the verification code sessionValidate.php

The code is as follows

代码如下

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session_start();     //在页首先要开启session,     //error_reporting(2047);     session_destroy();     //将session去掉，以每次都能取新的session值;     //用seesion 效果不错，也很方便     ?>                         此例为session验证实例         验证码：                 //打印上一个session;     echo "上一个session："._SESSION["authnum_session"]." ";     validate="";     if(isset(_POST["validate"])){     validate=_POST["validate"];     echo "您刚才输入的是："._POST["validate"]." 状态：";     if(validate!=_SESSION["authnum_session"]){     //判断session值与用户输入的验证码是否一致;     echo "输入有误";     }else{     echo "通过验证";     }     }     /*     //打印全部session;     PrintArr(_SESSION);     function PrintArr(aArray){     echo '';<br>     print_r(aArray);<br>     echo '';     }     */     ?>

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Session_start();

//On the page, you must first open the session,

//error_reporting(2047); Session_destroy(); //Remove the session so that you can get a new session value every time; //Using seesion works well and is very convenient ?> This example is a session verification instance

Verification code:

//Print the previous session; echo "Previous session:"._SESSION["authnum_session"]."
"; validate=""; If(isset(_POST["validate"])){ ​​ validate=_POST["validate"]; echo "What you just entered is: "._POST["validate"]."
Status:"; If(validate!=_SESSION["authnum_session"]){ //Determine whether the session value is consistent with the verification code entered by the user; echo "Incorrect input"; }else{ echo "passed verification"; } } /* //Print all sessions; PrintArr(_SESSION); Function PrintArr(aArray){ echo ''; Print_r(aArray); echo ''; } */ ?> http://www.bkjia.com/PHPjc/632824.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/632824.htmlTechArticleVerification code is a common function in WEB2.0 now, such as registration, login or message page , all require a registration code to verify the legitimacy of the current operator. We will see that some websites...